This invention relates generally to circuit breakers, and more particularly to a flat circuit breaker having a bi-metallic strip which is rounded and which can be used in the automotive industry.
Numerous flat circuit breakers have been used for decades and for a variety of applications. Certain ones, like those described in Patents GB No. 657 434 and 1,542,252 or FR No. 2,531,264, have bi-metallic strips provided with special cut-outs that demarcate at least one, central flexible lamina. Others, like those described in Patents FR No. 1,361,950 2,385,216 and 2,466,846, involve either bi-metallic strips with special cut-outs or a rectangular bi-metallic strip and a mobile contact held by the bi-metallic strip.
In the prior art circuit breakers the mobile part, generally consisting of a pushbutton, is moved between a bi-metallic strip contact and one held by a connecting tab that ensures an electrical continuity with the strip so as to interrupt an electrical feed whenever the strip is deformed as a result of a temperature rise occurring in said bi-metallic strip due to the Joule effect.
The major drawback with these circuit breakers is interposing an element between the fixed contact and the mobile one. Moreover, the need for making a cut-out in the bi-metallic strip in accordance with a special configuration implies not just very special tooling but also acceptance of somewhat-imprecise manufacturing tolerances for the strip on account of the nature of the metals used to make bi-metallic strips. Lastly, circuit breakers are not particularly flat because of superimposing of at least three elements, so such circuit breakers are not easily usable on automobile vehicles when there is so little room available where electrical connections are made.